Slimicidal composition and method



)6 gap r 3,426,134 SLIMICIDAL COMPOSITION AND METHOD Bernard F. Shema, Glenside, Pa., John P. Reilly, Cherry Hill, N..l., and Paul E. Kubasko, King of Prussia, Pa., assignors to Betz Laboratories, Inc., Philadelphia, Pa., a corporation of Pennsylvania No Drawing. Filed Mar. 9, 1966, Ser. No. 532,890

US. Cl. 424-302 Claims Int. Cl. A01n 9/18, 9/14 ABSTRACT OF THE ISCLOSURE The present invention relates to biocidal compositions for use in the control of slime-forming organisms in the water employed in paper or pulp mills, cooling systems and other industrial water systems, and particularly to compositions comprising the combination of methylene bis dithiocyanate and a his trihaloalkyl sulfone, and methods for employing these compositions.

The trihaloalkyl sulfones have deirionstrated high effi ciencies in the control of microorganisms present in the aqueous systems utilized in the manufacture of paper products, e.g., paper mill white water, and in cooling, e.g., the water used in cooling towers, air washers, and the like. The presence of microorganisms in suchsystems generally impairs their efficiency and in the case of paper and pulp products may irreparably contaminate and/or reduce the quality and production rate of the final product.

However, these sulfones cause lachrymation at comparatively low levels. For example, the presence of as little as 10 parts per million of these "compounds in the White water of a paper mill may cause extreme discomfort to the operating personnel. While higher concentrations may often be employed in cooling water, the same problems are experienced during unusual wind conditions, or if the cooling tower or air washer is located in proximity to an inhabited structure or area, or an air intake leading to such a structure or area.

. It is an object of the present invention to provide bi ocidal compositions which are effective at low concentrations against the microorganisms present in the water employed in paper and pulp mills, cooling systems and the like.

Another object is the provision of biocidal compositions which utilize the biocidal effectiveness of haloalkyl sulfones, while avoiding the lachrymation problem which otherwise attends the use of these compounds.

3,426,134 Patented Feb. 4, 1969 is provided by the haloalkyl sulfones may be exploited without the realization of a lachrymation problem. Furthermore, the combination provides an unexpected synergistic relationship in which the cooperative action of the combined ingredients yields a total effect which is greater thani'the sum of the effects of the two ingredients taken separately.

The methylene bis dithiocyanate which is employed by the invention possesses the formula CH (SCN) and is disclosed by vGerman Patents 520,330 and 545,740.

The haloalkyl sulfones utilized in the practice of the invention are bis-(trichloromethyl-sulfone and bis-(tribromomethyl)-sulfone, as disclosed by US. 2,959,517 and 3,051,757.

To demonstrate the synergism which is provided by the inventive combinations of compounds, as well as the low concentrations of bis-trihalomethyl sulfones which are made possible in the highly effective biocidal compositions of the inveiition, the data set forth in Table 1 has been prepared. In the preparation of this data, the concentrations of biocidal compositions indicated, were tested in a paper rnill white water sample which was secured a combined ingredients is many times as great as the additive effect of the individual ingredients and clearly indi-' cates the existence of synergism. At the same time, it may be observed that effective biocides are obtained while'the concentration of the lachrymation inducing sulfone is maintained at a low level. Samples 2 and 3 show that the combined ingredients yield a biocidal effect which is much greater than the additive effect of the ingredients contained by these combinations. Sample 4 more clearly demonstrates synergism since a concentration of the combined ingredients which is 37.5% less than the concentration of either of the ingredients used alone yields a biocidal effect which is 10% greater than the biocidal effect obtained when either of the ingredients is used alone in greater concentrations. A mere 1.2 5 p.p.m. of the inventive combination yields a 61.8% kill while 2 p.p.m. of methylene bis dithiocyanate yields a kill of only 56.2% and 2 p.p.m. of the sulfone actually permits the continued growth of the microorganisms.

TABLE 1 Quantity of Total Number 01 Percentage of Theoretical each individquantity or organisms mieroorgankilliftheefiect Sample Biocide ual bioeide biocide present after ismskilledby of the ingre- (p.p.m.) (p.p.m.) 3 hour the treatment dients was incubation merely additive 1 None-control 0 2,155,000 2(a) Methylene bisdithiocyanate- 0.5 0.5 3,500,000 2(b) 1?is-(trichlor( )meth yl)-sulione 2.0 2.0 2,350,000 2(0) Methylene bisdithlocyanate, b1 2. 320 000 1: 0 1. 0 2, 230, 000 I 4.0 4.0 s semesters:tatt8 000 4(a) Methylenebisdithioeyanate 2.0 2.0 950,000 4(b) Bis-(trichloromethyl)-sulfone 2.0 2.0 2,350,000 ?tizlissmzthystttazatt;. 1:53 i 1.25 830.000

Further evidence of the reduced lachrymatory poten- 6.67% inhibition. Similarly, each part per million of the tial of the inventive biocides is provided by Table 2 which dithiocyanate provides 25% inhibition. Accordingly, in an demonstrates the effectiveness of biocidal compositions 80:20 admixture of these ingredients it would be expected containing between 1-8 ppm. of the sulfone. These data that 7.740 ppm. of the sulfone, and 1.94 p.p.m. of the were also obtained with the white water sample employed dithiocyanate would be required for 100% inhibition, in Table l. in the absence of synergism.

It should be noted that when the inventive compositions are employed in the treatment of cooling or paper TABLE 2 mill water, they are preferably utilized in the form of T t 1 H i Q N f relatively dilute dispersions. For example, a preferred Sample qua it ity b s zizi' idhi o ome t l iy len bis Percentage dlsperslon Compnses between 5 to 65% by Welght of the No. o oc de y dithiocynnaw kill synergistic combination of biocides in admixture with zfgff various solvents and solubilizing agents. An example of 4 1 25 1 O 25 61 8 such a dispersion comprises 12.5% by weight of methyl 1:11:: 50 2 5 ene bis dithlocyanate, 12.5% by weight of bis-(trichlorog 3- 88 g methyl)-sulfone, and equal parts by weight of isopropanol, hexylene glycol and dimethyl formamide. Surfactants such The data set forth in Table 3 further indicates the imas the alkylarly polyether alcqhols Polyether alcohols proved results, synergistic effect, reduced sulfone content sulfoglates suflffates f mayfilsobe employiad and various sulfone: thiocyainate ratios, which may be m ance t dlspqrsabblty Stabl i Fhese achieved with, or employed in, the practice of the present 9 The q p dlsperslqns of t e blqcldal invention pos1t1ons are utilized in order to 1nsure th e rapid and uniform dispersib lity of the biocldes within the lndustral 40 water which is treated. It has been found that non-aqueous solvents are generally suitable in the preparation of. the TABLE 3 dispersions of the invention, e.g., alkyl benzene sulfonates Quantity and aromatic kerosenes. In the treatment of paper-mill and Minimum ffitical actualli cooling water eifective biocidal action is obtained when Sample Biocidal ingredients iv hi c li a h the (foncenfrailon trea'tmfmt level of the combmfed or No. would b pec achievement admixed bioc des, 1.e., dithiocyanate and sulfone, is beir iin l i fi i fifig lifi) tween 0.5 parts per million to 75 parts per million, and (uppreferably between 1 and 30 parts per million, based 8 Bis (trich1ommethy1) 15 upon the total content of the system treated, i.e., total sulfone. 4 quantity of cooling water or paper mill water. The com- 9 gfit gggg g g positions of the invention may be fed continuously to the 10 g g a g 0f 3 treated system, e.g., by means of a metered pump, or may be fed periodically at intervals calculated to control the 11 g g growth of slime-forming organisms in the system. Naturally, in the treatment of cooling water the feeding of the inventive compositions must be designed to compensate for blowdown in those systems which employ that expedient.

The data in Table 3 Was achieved y means f an agar In addition, the dithiocyanate and sulfone may be emsubstrate method in which the biocidal materials were ployed in varying ratios from 5 to 5; 5 although a added to a nutrient substrate which was then innoculated 20:80 ratio is preferred with Aer0bacter qerogenes. The quantity of the additives To specifically demonstrate the improved results and was Increased 1mm no Qrgamsn} growth could'be observed effectiveness of the inventive compositions in the form at the and of a 9 P h preferred for commercial application, the results set It may be that h synefglsnq' efiect g d e forth in Table 4 were derived. This data is based upon 80:20 of mgredlents mprefises t e e acme: studies conducted with white water obtained from a comness of the ingredients by 35%, while in the case of the 1 d f d b t 25:75 admixture a 32% increase is provided. At the same mercla Paper cqntrasts pre arm em Q {men time, the inventive admixtures permit the reduction of the f h t mventlon three commerclany avallabge quantity of the lac-hrymation inducing sulfone by 75% blocldes whlch are 9 and cunfmfly ,usfid m t e and 93%. The theoretical values for predictable quantities trefitnfent of P p 111111 White Water. S x cant evaluof the ingredients required for complete inhibition were anon Includes a three 110111 and a 51X P mlcl'oolganlsm calculated on the basis of the effectiveness of the ingredi' Count and all of the figuffis Set P Table 4 p eents. For example, since 15 p.p.m. of the sulfone are resent the percentage of microorganisms lulled by the variquired for 100% inhibition, each part per million yields ous biocides at the treatment levels indicated.

TABLE 4 A B C 1. Three hour contact time Biocide The Xs employed in the above table indicate a condition in which the growth of microorganisms was so great as to prevent an accurate count.

Biocide A comprises a preferred embodiment of the invention in which 25% by weight of a 4:1 admixture of bis(trichloromethyl)-sulfone and methylene bis dithiocyanate, respectively, are dispersed in equal parts by weight of isopropanol, hexylene glycol and dimethyl formamide. Biocide B contains a dispersion of 21% by weight of dimethyltetrahydro-l.3.5.2H-thiadiazine 2' thione and "6% by weight of mercaptobenzothiazole. Biocide C contains a dispersion of 20% by weight of bis(trichloromethyl)sulfone and 15% by weight of mixed N-alkyl dimethyll benzyl ammonium chlorides in which the mixed alkyl groups contain between 14-16 carbon atoms. Biocide D contains 24% by weight of sodium pentachlorophenate, 8.5% by weight of sodium 2,4,5-trichlrophenate, 4.1% of sodium salts of other c-hlorophenols, 4% of sodium dimethyl dithiocanbamate and 5% of mixed N-alkyl dimethyl benzyl ammonium chlorides in which the alkyl groups contain between 14-16 carbon atoms.

It must be noted that the inventive biocide yields a superior biocidal activity despite the fact that the other biocides contain a higher concentration of biocidal ingredients, i.e., 2745.6% by weight as contrasted with 25% by weight in the inventive composition. For example, the 25 concentration of the inventive composition yields a kill of 9799.3% at the 50 p.p.m. treatment level after 3 and 6 hours, whereas the biocide containing 45.6% of biocidal ingredients (Biocide D) yields a kill of 39.5-46.0% at the same treatment level. In all instances the inventive biocide is greatly superior to the commercially available biocides.

It should also be noted that at the 50 p.p.m. treatment levels of Table 4, the inventive composition contains only 10 p.p.m. of the sulfone and is therefore devoid of a lachrymation problem at those treatment levels. It must be realized that a 50 p.p.m. treatment with the dispersions of these biocides in a laboratory analysis, may be re placed by lower treatment levels in the actual treatment of a paper mill or cooling tower.

The results obtained with the foregoing combinations of methylene bis dithiocyanate and bis-(trichloromethyl)-= sulfone, may also be realized with the substitution of bis-(tribromomethyl)-sulfone for the chlorine substituted compound.

It should be noted that while the preponderance of the specification has dealt specifically with the treatment of the aqueous systems employed in paper and pulp mills and cooling systems, the compositions and methods of the present invention are broadly applicable to the treatment of industrial waters which are plagued by deposits formed by slime forming organisms, or by the very presence of such organisms.

It is apparent that biocidal compositions demonstrating extensive effectiveness in the treatment of paper-mill and cooling water, and methods for the use of these compositions, have been provided by the present invention. It is also apparent that the inventive compositions and methods permit low biocidal use concentrations, provide a synergistic effect, and permit the exploitation of the biocidal elfectiveness of the his (trihaloalkyl) sulfones with out the realization of a lachrymation problem which normany attends the use of these compounds.

We claim:

1. A slimicidal composition consisting essentially of an admixture of between 5 to 95% by weight of methylene bisdithiocyanate and between 95 to 5% by weight of bis- (trichloromethyl)-sulfone.

2. A slimicidal composition as claimed by claim 1 in which said dithiocyanate is present in a quantity of 20% by weight and said bis-(trichloromethyl)-sulfone is pres ent in a quantity of 80% by weight.

3. A slimicidal composition as claimed by claim 1 in which between 5 to 65% by weight of said admixture is dispersed in between 35 to 95% by weight of a non-aqueous solvent.

4. A slimicidal composition as claimed by claim 3 in which said non-aqueous solvent is a mixture of equal parts by weight of isopropanol, hexylene glycol and dimethyl formamide.

5. A slimicidal method for the control of slime in industrial water, comprising dispersing in said water between 0.5 to parts per million of an admixture of between 5 to 95% by weight of methylene bis dithiocyanate and between 95 to 5% by weight of bis-(trichloromethyl)= sulfone.

6. A slimicidal method as claimed by claim 5 in which said dithiocyanate is present in a quantity of 20% by weight and said bis-(trichloromethyl)-sulfone is present in a quantity of by weight.

7. A slimicidal method as claimed by claim 5 in which said admixture is added to said water as a dispersion of between 5 to 65% by weight of said admixture in between 35 to by weight of a non-aqueous solvent.

8. A slimicidal method as claimed by claim 7 in which said non-aqueous solvent is a mixture of equal parts by weight of isopropanol, hexylene glycol and dimethyl formamide.

9. A slimicidal method as claimed by claim 5 in which said industrial water is the aqueous component of an aqueous suspension of cellulosic pulp employed in the manufacture of paper and pulp.

10. A slimicidal method as claimed by claim 5 in which said industrial water is cooling water.

References Cited UNITED STATES PATENTS 2,959,517 11/1960 Bowers et al 167-22 3,051,757 8/ 1962 Johnston 167--22 3,252,855 5/1966 Wehner 106-45 XR ALBERT T. MEYERS, Primary Examiner.

D. R. MAHANAND, Assistant Examiner US. Cl. X.R.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3,426,134 Dated Feb. 4, 1969 Inventor(s) Bernard F. Shema et a1 It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

Substitute "methylene bi thiocyanate" for methylene bisdithiocyanate which appears in the patent as follows:

Column 1, line 33 Column 2., line 8, 19, 6O

Column 3, Table 1 Column 3, Table 2 Column 3, Table 3 Sample 2.(a)(c) Sample 9 Sample 3(a)(c) Sample 4(a)(c) Column 4, line 31 Column 5, lines 20, 5?

Column 6, line 14, 31

Substitute "thiocyanate for dithiocyanate which appears in the patent as follows:

Column 4, lines 18, 2.1, 46, 59 Column 6, lines 17, 35

Signed and sealed this 2nd day of May 1972.

(SEAL) Attest:

EDWARD M.FLEI'CHER, JR. ROBERT GOTTSCHALK Attest ing Officer Commissioner of Patents 

